Well, the code is P0372, Timing Reference High Resolution Signal A Too Few Pulses, which is showing twice on my reader. This code finally got thrown today as I had it scanned yesterday, and nothing showed up. However, I've had this problem for awhile now, but it's getting worse. Here's the problem I've been dealing with:

The car runs great on a cold start, just like normal everytime. Then after awhile (around 10 minutes or so?), it seems to just gradually run crappy, surging and sputtering, this proceeds untill it gets to the point of being undriveable, as there becomes essentailly no acceleration. Then, when i pull over at this point, if i let it idle it does extreme searching and now just recently it will gradually end up stalling. If this extremely low rpm searching starts to happen and I just jam it with gas, it stays alive but barely. Sometimes, if I just let it sit (while running, or just shut down), it ends up stopping the searching and sits at idle normally... then I can drive it for a little while, then the gradual surge will occur again.

Also, if I really kick it down after a cold start, it will sputter at around 4500 rpms in at least the first three gears.

The third thing is, after I'm driving for a little, if I push in my clutch and watch the rpms, the needle sinks to 2000 and sits for alittle bit, then sinks down to 1000 where it stays...

In hopes of solving this problem, I've put brand new plugs in and brand new wires. No result. I'm starting to form a radius around my house that I can safely drive and it seems to be shrinking (could be my imagination...). Thanks for your help with this one guys, if this can get solved soon, i will be truly grateful.

 

Optispark is toast, well on its way to being toast. Those symptoms are spot on with optispark failure. The cheapest place to find one. Is from Either Dal, or Calvin. I personally bought mine from calvin, for $227. He has upped it to 232 now i see though. Here is a link to him selling them on e-bay

http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WD1V

 

Well, I was afraid of that answer. I guess I'll order an opti right now... I noticed eBay site says he recommends getting a new vacuum harness too, should I'll order that as well?

 

hey mnfbody guy .I'm haveing the same sort of thing happening to the 95 Z28 I bought from dave95.

Same type of thing runs and idles ok at start and gets worse the more it heats up .The guy i bought it from said he put a new opti in about 1500 miles ago. Also the water pump was leaking out the weep hole and it might have taken out my opti. But talked to my brother and we are going to try the to change out the MAP sensor. From what I've read a bad MAP sensor could make your car run that way . It controls fuel and spark. I'm going to swap the one out of my 95Z and try it in the one I just bought hope this fixes it if not then on to the opti.

I'll let you know what happens and if you get yours fixed let me know what it was god hope it's not the opti I just replaced the water pump and was half way there and now might have to go into it again

 

I would change out everything and start fresh. New vacuum harness, new *upgraded* water pump *obviously*.

 

Well I tried the MAP from my other car and did'nt help at all on my problem.

How hot doe's your car get?

Mine runs fine cold but after about 10-20 min it get real hot and starts doing what your car is doing . Do your fans come on when it gets hot and starts to stumble. Mine don't seem to come on but I've checked the fans and the switches replaced the temp sensor still no help.

What I meen as to how hot doe's it get mine gets hot and the cat gets so hot steam or smoke is comeing from the out side of the cat and it smells real hot under the car.

Let me know what you find out is wrong with your car I;m stumped as to where to go next.

And yes my circle is getting less and less also, I'm almost worried to take it around the block at this piont

 

well, I think the highest I've seen my temp go is about 190ish? I have a new 160* thermostat in it... that's probably why. My fans are always running, right away when i start the car... this is a result of my pcmforless tune. So the car always runs pretty cool... It definitely sounds like a cooling problem for you, bro. Whats your name on mnfbody? I'm waiting for my new opti to come right now... then I'll replace that and let you know what happens

 

A 160* thermostat on a stock tune won't do you much. I take you it you have either a manual fan switch or a computer tune to kick your fans on sooner?

 

yep, i got the tune.

 

I have now bought the car from nvr2old. I have been searching for the problem for a week. The car runs awesome when it is cold but when it is warm (closed loop) it runs awesome but as soon as I come to a stop and then I want to take off it stumbles and knocks really bad unless I really baby it when I take off. As soon as I get going it runs awesome, I can floor it and it will take off like a bat out of hell. I just noticed that after driving for awhile after the stumbling starts it will start running rougher and eventually everytime I hit the gas it stumbles pretty bad and then takes off. I have checked/replaced the following things:

New plugs
Fuel pressure is right at 44psi w/ the vacuum hose off.
Took off the fuel pressure regulator and sucked on it really hard and got nothing so there is no tear in the diaphram. part must be ok
Checked the MAP w/ voltmeter and it is good
Checked the TPS w/ voltmeter and it is good
OPTI supposidly has only 1500 miles on it
Has a newer blaster coil
checked the resistence on the coil wire and it was 3.4 ohms and there was no visable wear so it must be ok.
Put on a Granatelli MAF
Drove car with ERG unplugged and problem was still there
Drove car with IAC unplugged and problem was still there
Drove car with coolant temp sensor unplugged and problem was still there
Drove car with air temp sensor unplugged and problem was still there
Drove car with knock sensor unplugged and problem was still there.

I can't think of anything else to check. The next thing I am going to do is put a 1000 ohm resister in the temp sensor plug so the computer thinks that the car is only at 115 degrees. I am thinking that the car has some kind of closed loop problem so by doing this the car will stay in open loop and if the problem goes away I know that there is either something wrong with the closed loop program or something that only operates in closed loop (EGR valve)

I am also having a buddy make a ALDL cable so we can do some datalogging to see if we can pin-point the problem.

please let me know if any of you have any suggestions